[syslinux] "Tick-counting" vs "Tick-less" timekeeping issues on VMs emulating BIOS PCs

Patrick Masotta masottaus at yahoo.com
Wed Mar 2 23:31:02 PST 2016




>>>

> Not really, a virtual environment can easily emulate the BIOS_timer    at 0x046C
> but it has problems emulating a "real" timer interrupt to be hooked...
> That's the real problem.

The timer interrupt works fine in at least KVM, Xen, VMware, and 
Hyper-V.  (I've tested iPXE in all of those virtual environments, and 
iPXE relies on the timer interrupt actually triggering a call to an ISR 
within the VM.)


Michael
<<<


Well, that contradicts what the VMware document says.
I'm still working on this; probably there are other hidden timing 

issues affecting TFTP when it's run on a VM. I'll post what I find.

Best,
Patrick


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